Senior Backend Engineer – Distributed Security Platform

NightDragon Acquisition Corp.; United States; On-site; USD 170,000 - 235,000; Full time

Benefits offered by this job

Inclusive Team

Growth Opportunities

Innovative Culture

Hybrid & Remote Work

Competitive Compensation

Job summary

Horizon3 is a remote cybersecurity innovator delivering NodeZero platform capabilities for autonomous pentests and defensive agents. As Senior Backend Engineer on the Defensive Agent team, you’ll build the scalable platform that runs agents across thousands of tenants, ensuring isolation, security, and composable workflows.

You’ll own the runtime, tool layer, orchestration, and observability, working with AI researchers to ship safe, production-ready capabilities and to enable data-driven

Qualifications

• Bachelor's degree in CS/CE or related field.
• 7+ years of professional software engineering experience.
• Experience on cloud platforms (AWS, Azure, GCP) and containers (Docker, Kubernetes).
• Expert proficiency in SQL.
• Experience designing and operating distributed systems in production.
• Track record of shipping and operating production services, including on-call ownership.

Responsibilities

• Build and own the agent execution runtime with durable, resumable workflows.
• Design and implement the tool layer with registry, versioning, validation, and tenant isolation.
• Build the connector framework for third-party security controls.
• Implement safe-change pipeline with dry-run, simulation, gates, rollback, and audit trails.
• Extend multi-tenant isolation for agents with write actions and egress controls.
• Develop ETL and GraphQL features to support context, history, and remediation state.
• Build ETL pipelines turning pentest results into research datasets.
• Instrument with distributed tracing and cost accounting.
• Collaborate with AI researchers to move capabilities from prototype to production.

Skills

Distributed systems

Cloud platforms

SQL

On-call ownership

LLM/agentic systems

Education

Bachelor's Degree in Computer Science or related field

Tools

Docker

Kubernetes

Temporal

PostgreSQL

Neo4j

GraphQL

Job description

Horizon3 is a remote cybersecurity innovator delivering NodeZero platform capabilities for autonomous pentests and defensive agents. As Senior Backend Engineer on the Defensive Agent team, you’ll build the scalable platform that runs agents across thousands of tenants, ensuring isolation, security, and composable workflows.

You’ll own the runtime, tool layer, orchestration, and observability, working with AI researchers to ship safe, production-ready capabilities and to enable data-driven